The hallmark of the conspiracy theorist is the perceived ability to "connect the dots" where no such connections exist. Of course, the theorist rejects the term "theorist" because, he insists, he is merely making objective observations. In the days before the internet, he would feverishly spend hours clipping newspaper articles at his kitchen table, circling clues with a red pen and shouting "Aha!" to a room full of ghosts, who might or might not see the obvious linkages between the latest football scores and tank movement outside Irkutsk.

Today, conspiracy theorists are far less exotic. But what they lack in idiosyncratic charm, they more than make up in self-importance. Consider Stephen M. Walt, a leading "realist" foreign-policy guru, who co-authored (with John Mearsheimer) The Israel Lobby, which purports to prove that pro-Israel fifth columnists are distorting America's foreign policy for Israel's benefit. These savvy agents of Zion - the bagel-guzzling cabal of evil-doers, not the authors - are mostly Jews with dual loyalties who will bully anyone who dares criticise the Jewish state. Walt's Protocols of the Elders of Realism was hailed as profound and serious by many of Israel's harshest critics, and attacked as everything from sloppy and hyperbolic to irresponsible and even anti-Semitic by almost everyone else, including the New York Times, Foreign Affairs and even The Nation (not a hotbed of Likudniks).

A perfect illustration of Walt's paranoid tendency was his bilious defence of Charles ("Chas") Freeman, Barack Obama's now-withdrawn choice to run the US National Intelligence Council (NIC). Freeman has famously "realistic" views on foreign policy, albeit the sort of realism that balms the conscience as you deposit Saudi cheques. As the president of the Saudi-backed Middle East Policy Council, the former US ambassador to Riyadh could have been be counted on to say exactly what the House of Saud wanted him to say. Walt's theory is that a "despicable smear campaign" was launched by the "usual suspects". Freeman himself was in no doubt who was to blame for his withdrawal. "The tactics of the Israel Lobby plumb the depths of dishonour and indecency," he raged.

Writing on Foreign Policy's website, Walt recounted "Senator Joseph McCarthy's infamous witch-hunt against alleged communists". He continued: "After McCarthy had falsely accused a young army officer of being a communist agent, army counsel Joseph Welch...shot back: ‘At long last, Senator McCarthy, have you not a shred of decency?'"

Walt enlists this hackneyed tale of speaking-truth-to-power as a means of attacking Freeman's critics. But he can't stop hacking away at the facts to make them fit. For starters, he gets Welch's quote wrong (impressive, since it can be Googled in seconds). Moreover, the accusation wasn't that a young army officer was a communist agent, but that an associate of Welch's was a member of the National Lawyers' Guild, a communist front. Welch's complaint about McCarthy's lack of decency was a great show that successfully distracted from the relevant facts.

The irony is that Walt wants to do the same, only this time he's the one acting like McCarthy. Walt sees a "thunderous, co-ordinated assault" from the usual suspects: "Jonathan Chait of the New Republic, Michael Goldfarb at the Weekly Standard, Jeffrey Goldberg of the Atlantic, Gabriel Schoenfeld (writing on the op-ed page of the Wall Street Journal), Jonah Goldberg of National Review, Marty Peretz on his New Republic blog and former AIPAC [American-Israel Public Affairs Comittee] official Steve Rosen (yes, the same guy who is now on trial for passing secret information to Israel)."

What brings us all together? According to Walt, it's that Freeman has uttered "rather mild public criticisms of Israel". But that isn't our only bond. After all, how could we be "thunderously co-ordinated" if that was our only connection? Walt suggests that we "usual suspects" are less than fully American. After all, Walt assures us that Freeman is a "true patriot", unlike Jeffrey Goldberg who-hint, hint-once served in the Israeli army. One problem: I've never met Rosen or Goldberg (no relation) or Peretz or Schoenfeld and I co-ordinated with none of them. Until Walt's diatribe, I had barely criticised Freeman. All I did was link, on National Review's blog, to two posts by other critics. Most of his critics had called attention to his connections to China (he was on the board of the government-owned Chinese National Offshore Oil Corporation). He once argued that Beijing's biggest mistake at Tiananmen Square was to not crush the dissidents more thoroughly. Even more revealing, Walt singled me out from some National Review colleagues who had criticised Freeman at greater length. It seems those dots were camouflaged with non-Jewish surnames like McCarthy and Hanson. That, it seems, is all it takes to stay off his list of "usual suspects".

If Walt was better at connecting dots, he might ask himself if he has, at long last, any decency.